utf8_decode

    (PHP 4, PHP 5, PHP 7, PHP 8)

    utf8_decode — Converts a string from UTF-8 to ISO-8859-1, replacing invalid or unrepresentable characters

    Warning

    This function has been DEPRECATED as of PHP 8.2.0. Relying on this function is highly discouraged.

    Description

    utf8_decode(string$string): string

    This function converts the string string from the UTF-8 encoding to ISO-8859-1. Bytes in the string which are not valid UTF-8, and UTF-8 characters which do not exist in ISO-8859-1 (that is, code points above U+00FF) are replaced with ?.

    Note:

    Many web pages marked as using the ISO-8859-1 character encoding actually use the similar Windows-1252 encoding, and web browsers will interpret ISO-8859-1 web pages as Windows-1252. Windows-1252 features additional printable characters, such as the Euro sign (€) and curly quotes (“”), instead of certain ISO-8859-1 control characters. This function will not convert such Windows-1252 characters correctly. Use a different function if Windows-1252 conversion is required.

    Parameters

    string

    A UTF-8 encoded string.

    Return Values

    Returns the ISO-8859-1 translation of string.

    Changelog

    VersionDescription
    8.2.0 This function has been deprecated.
    7.2.0 This function has been moved from the XML extension to the core of PHP. In previous versions, it was only available if the XML extension was installed.

    Examples

    Example #1 Basic examples

    <?php
    // Convert the string 'Zoë' from UTF-8 to ISO 8859-1
    $utf8_string = "\x5A\x6F\xC3\xAB";
    $iso8859_1_string = utf8_decode($utf8_string);
    echo     bin2hex($iso8859_1_string), "\n";

    // Invalid UTF-8 sequences are replaced with '?'
    $invalid_utf8_string = "\xC3";
    $iso8859_1_string = utf8_decode($invalid_utf8_string);
    var_dump($iso8859_1_string);

    // Characters which don't exist in ISO 8859-1, such as
    // '€' (Euro Sign) are also replaced with '?'
    $utf8_string = "\xE2\x82\xAC";
    $iso8859_1_string = utf8_decode($utf8_string);
    var_dump($iso8859_1_string);
    ?>

    The above example will output:

    5a6feb string(1) "?" string(1) "?"

    Notes

    Note: Deprecation and alternatives

    This function is deprecated as of PHP 8.2.0, and will be removed in a future version. Existing uses should be checked and replaced with appropriate alternatives.

    Similar functionality can be achieved with mb_convert_encoding(), which supports ISO-8859-1 and many other character encodings.

    <?php
    $utf8_string     = "\xC3\xAB"; // 'ë' (e with diaeresis) in UTF-8
    $iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
    echo     bin2hex($iso8859_1_string), "\n";

    $utf8_string = "\xCE\xBB"; // 'λ' (Greek lower-case lambda) in UTF-8
    $iso8859_7_string = mb_convert_encoding($utf8_string, 'ISO-8859-7', 'UTF-8');
    echo     bin2hex($iso8859_7_string), "\n";

    $utf8_string = "\xE2\x82\xAC"; // '€' (Euro sign) in UTF-8 (not present in ISO-8859-1)
    $windows_1252_string = mb_convert_encoding($utf8_string, 'Windows-1252', 'UTF-8');
    echo     bin2hex($windows_1252_string), "\n";
    ?>

    The above example will output:

    eb eb 80

    Other options which may be available depending on the extensions installed are UConverter::transcode() and iconv().

    The following all give the same result:

    <?php
    $utf8_string     = "\x5A\x6F\xC3\xAB"; // 'Zoë' in UTF-8
    $iso8859_1_string = utf8_decode($utf8_string);
    echo     bin2hex($iso8859_1_string), "\n";

    $iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
    echo     bin2hex($iso8859_1_string), "\n";

    $iso8859_1_string = iconv('UTF-8', 'ISO-8859-1', $utf8_string);
    echo     bin2hex($iso8859_1_string), "\n";

    $iso8859_1_string = UConverter::transcode($utf8_string, 'ISO-8859-1', 'UTF8');
    echo     bin2hex($iso8859_1_string), "\n";
    ?>

    The above example will output:

    5a6feb 5a6feb 5a6feb 5a6feb
    Specifying '?' as the 'to_subst' option to UConverter::transcode() gives the same result as utf8_decode() for strings which are invalid or which can not be represented in ISO 8859-1.
    <?php
    $utf8_string     = "\xE2\x82\xAC"; // € (Euro Sign) does not exist in ISO 8859-1
    $iso8859_1_string = UConverter::transcode(
    $utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
    );
    var_dump($iso8859_1_string);
    ?>

    The above example will output:

    sring(1) "?"

    See Also

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